New Butenolides and Cyclopentenones from Saline Soil-Derived Fungus Aspergillus Sclerotiorum

Abstract

Three new <i>γ</i>-hydroxyl butenolides (<b>1</b>-<b>3</b>), a pair of new enantiomeric spiro-butenolides (<b>4a</b> and <b>4b</b>), a pair of enantiomeric cyclopentenones (<b>5a</b> new and <b>5b</b> new natural), and six known compounds (<b>6</b>-<b>11</b>), were isolated from <i>Aspergillus sclerotiorum</i>. Their structures were established by spectroscopic data and electronic circular dichroism (ECD) spectra. Two pairs of enantiomers [(+)/(-)-<b>6c</b> and (+)/(-)-<b>6d</b>] obtained from the reaction of <b>6</b> with acetyl chloride (AcCl) confirmed that <b>6</b> was a mixture of two pairs of enantiomers. In addition, the X-ray data confirmed that <b>7</b> was also a racemate. The new metabolites (<b>1</b>-<b>5)</b> were evaluated for their inhibitory activity against cancer and non-cancer cell lines. As a result, compound <b>1</b> exhibited moderate cytotoxicity to HL60 and A549 with IC₅₀ values of 6.5 and 8.9 µM, respectively, and weak potency to HL-7702 with IC₅₀ values of 17.6 µM. Furthermore, compounds <b>1</b>-<b>9</b> were screened for their antimicrobial activity using the micro-broth dilution method. MIC values of 200 μg/mL were obtained for compounds <b>2</b> and <b>3</b> towards <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>, while compound <b>8</b> exhibited a MIC of 50 μ/mL towards <i>Candida albicans</i>.